Nano-sized silica supported FeCl3 as an efficient heterogeneous catalyst for the synthesis of 1,2,4-triazine derivatives

Article abstract of DOI:10.1016/S1872-2067(15)60829-4

The one-pot synthesis of a series of 1,2,4-triazines from the reactions of semicarbazide or thiosemicarbazide with various α,β-dicarbonyl compounds under reflux conditions in a EtOH-H₂O (9:1) mixture as solvent and catalyzed by nano-sized silica supported FeCl₃ (FeCl₃@SiO₂) was investigated. The FeCl₃ content of the catalyst was measured by atomic absorption to get the adsorption capacity. The reactions gave high yields of the product and the catalyst was easily separated and reused for successive reaction runs without significant loss of activity.

Full text of DOI:10.1016/S1872-2067(15)60829-4

ChineseꢀJournalꢀofꢀCatalysisꢀ36ꢀ(2015)ꢀ620–625
ꢀ
ꢀ ꢀ ꢀ
ꢀ ꢀ ꢀ ꢀ
a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m
ꢀ
j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / c h n j c
ꢀ
ꢀ
Article
Nano‐sizedꢀsilicaꢀsupportedꢀFeCl ꢀasꢀanꢀefficientꢀheterogeneousꢀ
3
catalystꢀforꢀtheꢀsynthesisꢀofꢀ1,2,4‐triazineꢀderivativesꢀ
ꢀ
DavoodꢀHabibi*,ꢀSomayyehꢀVakili
ꢀ
DepartmentꢀofꢀOrganicꢀChemistry,ꢀFacultyꢀofꢀChemistry,ꢀBu‐AliꢀSinaꢀUniversity,ꢀ6517838683,ꢀHamedan,ꢀIranꢀ
A R T I C L E ꢀ I N F O ꢀ
A B S T R A C T ꢀ
Articleꢀhistory:ꢀ
Theꢀone‐potꢀsynthesisꢀofꢀaꢀseriesꢀofꢀ1,2,4‐triazinesꢀfromꢀtheꢀreactionsꢀofꢀsemicarbazideꢀorꢀthiosemi‐
Receivedꢀ21ꢀSeptemberꢀ2014ꢀ
Acceptedꢀ19ꢀDecemberꢀ2014ꢀ
Publishedꢀ20ꢀAprilꢀ2015ꢀ
carbazideꢀ withꢀ variousꢀ α,β‐dicarbonylꢀ compoundsꢀ underꢀ refluxꢀ conditionsꢀ inꢀ aꢀ EtOH‐H
mixtureꢀasꢀsolventꢀandꢀcatalyzedꢀbyꢀnano‐sizedꢀsilicaꢀsupportedꢀFeCl ꢀ(FeCl @SiO )ꢀwasꢀinvestigat‐
ed.ꢀTheꢀFeCl ꢀcontentꢀofꢀtheꢀcatalystꢀwasꢀmeasuredꢀbyꢀatomicꢀabsorptionꢀtoꢀgetꢀtheꢀadsorptionꢀca‐
2
Oꢀ (9:1)ꢀ
3
3
2
3
pacity.ꢀTheꢀreactionsꢀgaveꢀhighꢀyieldsꢀofꢀtheꢀproductꢀandꢀtheꢀcatalystꢀwasꢀeasilyꢀseparatedꢀandꢀre‐
usedꢀforꢀsuccessiveꢀreactionꢀrunsꢀwithoutꢀsignificantꢀlossꢀofꢀactivity.ꢀ
Keywords:ꢀ
Nano‐sizedꢀsilicaꢀsupportedꢀFeCl3ꢀ
Multicomponentꢀreactionsꢀ
©ꢀ2015,ꢀDalianꢀInstituteꢀofꢀChemicalꢀPhysics,ꢀChineseꢀAcademyꢀofꢀSciences.
PublishedꢀbyꢀElsevierꢀB.V.ꢀAllꢀrightsꢀreserved.
1,2,4‐Triazinesꢀ
α,β‐Dicarbonylꢀcompoundsꢀ
Semicarbazideꢀ
Thiosemicarbazide
1
.ꢀ ꢀ Introductionꢀ
areasꢀ[8].ꢀTheꢀadvantagesꢀofꢀtheseꢀnano‐particlesꢀincludeꢀhighꢀ
activity,ꢀstrongꢀoxidizingꢀability,ꢀmoderateꢀtoꢀhighꢀLewisꢀacidity,ꢀ
non‐toxicity,ꢀreusability,ꢀandꢀlongꢀtermꢀstabilityꢀ[9,10].ꢀTheꢀsizeꢀ
ofꢀ theꢀ nanoꢀ particleꢀ asꢀ adsorbentꢀ determinesꢀ itsꢀ adsorptionꢀ
capacityꢀ[11].ꢀ
Recently,ꢀtheꢀuseꢀofꢀsilicaꢀsupportedꢀreagentsꢀhasꢀreceivedꢀ
considerableꢀimportanceꢀinꢀorganicꢀsynthesesꢀbecauseꢀofꢀtheirꢀ
easeꢀ ofꢀ handling,ꢀ enhancedꢀ reactionꢀ rates,ꢀ betterꢀ selectivity,ꢀ
simpleꢀworkup,ꢀlowꢀcost,ꢀeaseꢀofꢀpreparation,ꢀandꢀrecoverabil‐
ityꢀofꢀcatalysts.ꢀInꢀtheꢀpastꢀfewꢀyears,ꢀsilicaꢀsupportedꢀacidsꢀlikeꢀ
Solidꢀ supportedꢀ FeCl ꢀ hasꢀ beenꢀ widelyꢀ usedꢀ asꢀ aꢀ reusableꢀ
3
andꢀefficientꢀheterogeneousꢀcatalystꢀinꢀorganicꢀsyntheses.ꢀForꢀ
example,ꢀ polyanilineꢀ nano‐fiberꢀ supportedꢀ FeCl ꢀ wasꢀ usedꢀ asꢀ
theꢀcatalystꢀforꢀtheꢀacylationꢀofꢀalcoholsꢀandꢀaminesꢀ[1].ꢀRiceꢀ
huskꢀsupportedꢀFeCl ꢀnanoparticlesꢀwasꢀusedꢀforꢀtheꢀchemose‐
lectiveꢀ1,1‐diacetateꢀprotectionꢀandꢀdeprotectionꢀofꢀaldehydesꢀ
2].ꢀPolymerꢀsupportedꢀFeCl3ꢀwasꢀusedꢀ asꢀtheꢀcatalystꢀ forꢀtheꢀ
3
3
[
highꢀ yieldꢀ synthesisꢀ ofꢀ 1,5‐benzodiazepineꢀ derivativesꢀ underꢀ
solventꢀ freeꢀ conditionsꢀ andꢀ microwaveꢀ irradiationꢀ [3].ꢀ Silicaꢀ
silicaꢀsulfuricꢀacidꢀ[12],ꢀBF
3
·SiO2ꢀ[13],ꢀsilicaꢀgel/NaHSO4ꢀ[14]ꢀorꢀ
3
supportedꢀ FeCl ꢀ wasꢀ usedꢀ inꢀ variousꢀ organicꢀ reactionsꢀ [4–6].ꢀ
HClO ‐SiO2ꢀ[15],ꢀhaveꢀreceivedꢀsignificantꢀattentionꢀasꢀefficientꢀ
4
Recently,ꢀweꢀusedꢀFeCl
lystꢀ forꢀ theꢀ synthesisꢀ ofꢀ 5‐substitutedꢀ 1H‐tetrazolesꢀ viaꢀ [2+3]ꢀ
cycloadditionꢀofꢀnitrilesꢀandꢀsodiumꢀazideꢀ[7].ꢀ ꢀ
Currently,ꢀ nano‐particlesꢀ haveꢀ attractedꢀ considerableꢀ re‐
searchꢀinterestꢀasꢀanꢀefficientꢀsupportꢀforꢀhomogeneousꢀcata‐
lystsꢀ inꢀ syntheticꢀ chemistryꢀ dueꢀ toꢀ theirꢀ highꢀ specificꢀ surfaceꢀ
3
‐SiO ꢀasꢀaꢀreusableꢀheterogeneousꢀcata‐
2
catalystsꢀinꢀvariousꢀorganicꢀtransformationsꢀdueꢀtoꢀtheirꢀhighꢀ
acidity,ꢀeasyꢀhandling,ꢀandꢀlowꢀcost.ꢀ ꢀ
Mostꢀheterocyclesꢀ participateꢀinꢀtheꢀmetabolicꢀpathwayꢀofꢀ
liveꢀorganismsꢀandꢀperformꢀseveralꢀbiochemicalꢀfunctionsꢀandꢀ
areꢀwidelyꢀusedꢀinꢀmedicineꢀindustry.ꢀNearlyꢀ60%ꢀofꢀtheꢀphar‐
maceuticalsꢀ usedꢀ inꢀ therapeuticꢀ systemsꢀ areꢀ N‐functionalizedꢀ
*ꢀCorrespondingꢀauthor. Tel:ꢀ+98‐81‐38380922;ꢀFax:ꢀ+98‐81‐38380709;ꢀE‐mail:ꢀdavood.habibi@gmail.comꢀ
DOI:ꢀ10.1016/S1872‐2067(15)60829‐4ꢀ|ꢀhttp://www.sciencedirect.com/science/journal/18722067ꢀ|ꢀChin.ꢀJ.ꢀCatal.,ꢀVol.ꢀ36,ꢀNo.ꢀ4,ꢀAprilꢀ2015ꢀ ꢀ ꢀ

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DavoodꢀHabibiꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ36ꢀ(2015)ꢀ620–625ꢀ
621ꢀ
heterocycles.ꢀOneꢀofꢀtheꢀimportantꢀtypeꢀofꢀtheꢀN‐functionalizedꢀ
heterocyclesꢀ areꢀ 1,2,4‐triazines.ꢀ Itꢀ hasꢀ beenꢀ reportedꢀ thatꢀ theꢀ
mL)ꢀandꢀtheꢀmixtureꢀwasꢀstirredꢀforꢀ24ꢀhꢀatꢀ20ꢀ°C.ꢀTheꢀresultingꢀ
mixtureꢀwasꢀcentrifugedꢀandꢀfilteredꢀandꢀtheꢀsolidꢀmaterialꢀwasꢀ
stirredꢀinꢀfreshꢀEtOAcꢀ(25ꢀmL)ꢀforꢀaꢀfurtherꢀ1ꢀh.ꢀTheꢀconcentra‐
1,2,4‐triazineꢀderivativesꢀpossessꢀaꢀbroadꢀspectrumꢀofꢀbiologi‐
3+ꢀ
calꢀ activities.ꢀ Forꢀ example,ꢀ theyꢀ haveꢀ shownꢀ antifungalꢀ [16],ꢀ
anti‐cancerꢀ [17],ꢀ anti‐bacterialꢀ [18],ꢀ analgesicꢀ [19],ꢀ andꢀ an‐
ti‐tumorꢀactivitiesꢀ[20,21].ꢀ ꢀ
tionꢀofꢀtheꢀremainingꢀFe inꢀtheꢀseparatedꢀsolutionꢀwasꢀdeter‐
minedꢀbyꢀatomicꢀabsorption.ꢀTheꢀFeCl ꢀcontentꢀofꢀtheꢀpreparedꢀ
catalystꢀwasꢀ66.9ꢀmgꢀofꢀFeCl ꢀperꢀgꢀofꢀFeCl @SiO .ꢀAsꢀindicatedꢀ
inꢀtheꢀTEMꢀimageꢀofꢀFeCl @SiO ꢀ(Fig.ꢀ1),ꢀnoꢀdetectableꢀchangeꢀ
3
3
3
2
Theꢀ reactionsꢀ ofꢀ α,β‐dicarbonylꢀ compoundsꢀ withꢀ variousꢀ
α,γ‐nucleophilesꢀ likeꢀ semicarbazideꢀ orꢀ thiosemicarbazideꢀ areꢀ
importantꢀ proceduresꢀ forꢀ theꢀ synthesisꢀ ofꢀ triazinesꢀ [22–25].ꢀ
Manyꢀofꢀtheseꢀmethodsꢀhaveꢀdrawbacksꢀsuchꢀasꢀlowꢀyieldsꢀorꢀ
prolongedꢀ timeꢀ periodꢀ andꢀ applicationꢀ ofꢀ hazardousꢀ andꢀ ex‐
pensiveꢀ catalystsꢀ orꢀ solvents.ꢀ Therefore,ꢀ theꢀ developmentꢀ ofꢀ
greener,ꢀ clean,ꢀ andꢀ environmentallyꢀ friendlyꢀ approachesꢀ isꢀ
desirable.ꢀ
3
2
inꢀtheꢀsizeꢀwasꢀobservedꢀafterꢀtheꢀadsorptionꢀofꢀFeCl
3
ꢀonꢀtheꢀ
nano‐sizedꢀsilica.ꢀ ꢀ ꢀ
2.3.ꢀ ꢀ Generalꢀprocedureꢀforꢀtheꢀone‐potꢀsynthesisꢀofꢀ1,2,4‐triazinꢀ
derivativesꢀ
Aꢀ mixtureꢀ ofꢀ α,β‐dicarbonylꢀ substratesꢀ (1ꢀ mmol),ꢀ semi‐
Unfortunately,ꢀtheꢀadsorptionꢀcapacityꢀofꢀtheꢀadsorbentꢀwasꢀ
carbazideꢀorꢀthiosemicarbazideꢀ(1ꢀmmol)ꢀandꢀFeCl
3
@SiO ꢀ(25ꢀ
2
notꢀcalculated,ꢀandꢀtheꢀpreciseꢀamountꢀofꢀFeCl
3
ꢀonꢀtheꢀcatalystꢀ
mg)ꢀinꢀEtOH‐H Oꢀ(9:1,ꢀ5ꢀmL)ꢀmixtureꢀasꢀaꢀsolventꢀwasꢀrefluxed.ꢀ
2
wasꢀnotꢀknownꢀinꢀmostꢀreactions.ꢀAlso,ꢀtheꢀleachingꢀprobabilityꢀ
ofꢀFeCl3ꢀfromꢀtheꢀsurfaceꢀofꢀtheꢀcatalystꢀwasꢀnotꢀinvestigatedꢀinꢀ
mostꢀ reports.ꢀ Soꢀ thereꢀ areꢀ demandsꢀ forꢀ preparingꢀ theꢀ rightꢀ
Afterꢀ completionꢀ ofꢀ theꢀ reaction,ꢀ whichꢀ wasꢀ monitoredꢀ withꢀ
TLC,ꢀ theꢀ resultingꢀ mixtureꢀ wasꢀ filteredꢀ andꢀ theꢀ solidꢀ wasꢀ
washedꢀ withꢀ EtOAcꢀ andꢀ H
2
O.ꢀ Theꢀ structuresꢀ ofꢀ theꢀ resultingꢀ
productsꢀ wereꢀ establishedꢀ onꢀ theꢀ basisꢀ ofꢀ theirꢀ Hꢀ NMR,ꢀ 13Cꢀ
1
supportedꢀcatalystꢀwithꢀtheꢀmostꢀefficientꢀcontentꢀofꢀFeCl
3
ꢀforꢀ
synthesizingꢀorganicꢀintermediatesꢀandꢀfineꢀchemicals.ꢀ ꢀ
NMR,ꢀandꢀCHNꢀanalysis.ꢀ
Concerningꢀtheꢀversatilityꢀandꢀhighꢀefficiencyꢀofꢀsolidꢀsup‐
portedꢀ FeCl ,ꢀ andꢀ theꢀ importanceꢀ ofꢀ theꢀ substitutedꢀ
,2,4‐triazines,ꢀhereꢀweꢀreportꢀtheꢀone‐potꢀsynthesisꢀofꢀaꢀseriesꢀ
6,7‐Dihydro‐5‐methyl‐5H‐cyclopenta[e][1,2,4]triazine‐3‐olꢀ
ꢀ
–1
3
(Entryꢀ1).ꢀPaleꢀyellowꢀsolid;ꢀmpꢀ=ꢀ250–252ꢀᵒC;ꢀIRꢀ(KBr,ꢀcm ):ꢀνꢀ
1
1
3500,ꢀ3000,ꢀ1689;ꢀ HꢀNMRꢀ(DMSO,ꢀ90ꢀMHz):ꢀδꢀ6.4ꢀ(m,ꢀ5H),ꢀ1.09ꢀ
ofꢀ1,2,4‐triazinesꢀfromꢀtheꢀreactionsꢀofꢀsemicarbazideꢀorꢀthio‐
(d,ꢀ 3H),ꢀ 11.03ꢀ (s,ꢀ 1H)ꢀ andꢀ 9.5ꢀ (s,ꢀ 1H);ꢀ 13Cꢀ NMRꢀ (DMSO,ꢀ 22.5ꢀ
semicarbazideꢀ withꢀ variousꢀ α,β‐dicarbonylꢀ compoundsꢀ underꢀ
MHz):ꢀδꢀ11,ꢀ22.5,ꢀ27,ꢀ32.7,ꢀ137.5,ꢀ148ꢀandꢀ154;ꢀAnal.ꢀCalcdꢀforꢀ
refluxꢀ inꢀ aꢀ EtOH‐H
2
Oꢀ (9:1)ꢀ mixtureꢀ asꢀ solventꢀ withꢀ aꢀ
C
7
H
9
N
3
Oꢀ(%):ꢀCꢀ55.62,ꢀHꢀ6.00,ꢀNꢀ27.80,ꢀOꢀ10.58;ꢀFoundꢀ(%):ꢀCꢀ
54.43;ꢀHꢀ5.2,ꢀNꢀ31.51,ꢀOꢀ8.86.ꢀ
,6‐Diphenyl‐1,2,4‐triazine‐3‐olꢀ(Entryꢀ2).ꢀPaleꢀwhiteꢀsolid;ꢀ
FeCl @SiO ꢀcatalystꢀ(Schemeꢀ1).ꢀ ꢀ ꢀ
3
2
5
–1
1
2.ꢀ ꢀ Experimentalꢀ
mpꢀ=ꢀ231–233ꢀᵒC;ꢀIRꢀ(KBr,ꢀcm ):ꢀνꢀ3500,ꢀ3300,ꢀ1687;ꢀ HꢀNMRꢀ
DMSO,ꢀ90ꢀ MHz):ꢀ δꢀ 7.0ꢀ (m,ꢀ 11H)ꢀ andꢀ 13.51ꢀ (s,ꢀ 1H);ꢀ 13Cꢀ NMRꢀ
(DMSO,ꢀ22.5ꢀ MHz):ꢀ δꢀ 127.99,ꢀ 128.16,ꢀ 128.77,ꢀ 128.93,ꢀ 129.28,ꢀ
30.78,ꢀ134.48,ꢀ135.73,ꢀ142.30,ꢀ153.35ꢀandꢀ167.28;ꢀAnal.ꢀCalcdꢀ
forꢀC15 Oꢀ(%):ꢀCꢀ72.28,ꢀHꢀ4.45,ꢀNꢀ16.86,ꢀOꢀ6.42;ꢀFoundꢀ(%):ꢀ
(
2.1.ꢀ ꢀ Materialꢀandꢀinstrumentsꢀ
1
SemicarbazideꢀHCl,ꢀthiosemicarbazide,ꢀSiO2ꢀofꢀvariousꢀparti‐
H N
11 3
cleꢀsizesꢀandꢀα,β‐dicarbonylꢀcompounds,ꢀwereꢀpurchasedꢀfromꢀ
Merckꢀ Chemicalꢀ Companyꢀ andꢀ usedꢀ withoutꢀ furtherꢀ purifica‐
tion.ꢀ IRꢀ spectraꢀ wereꢀ recordedꢀ onꢀ aꢀ Brukerꢀ 500ꢀ spectropho‐
tometerꢀ withꢀ KBrꢀ pellets.ꢀ Hꢀ andꢀ 13Cꢀ NMRꢀ spectraꢀ wereꢀ ob‐
tainedꢀ onꢀ aꢀ Brukerꢀ 300ꢀ MHzꢀ Avanceꢀ spectrometerꢀ withꢀ
Cꢀ71.12,ꢀHꢀ4.61,ꢀNꢀ17.51,ꢀOꢀ6.76.ꢀ
5H‐[1,2,4]triazino[5,6‐b]indol‐3‐olꢀ (Entryꢀ 3).ꢀ Paleꢀ yellowꢀ
–1
1
solid;ꢀmpꢀ=ꢀ281–283ꢀᵒC;ꢀIRꢀ(KBr,ꢀcm ):ꢀνꢀ3470,ꢀ3300,ꢀ1700;ꢀ Hꢀ
NMRꢀ(DMSO,ꢀ90ꢀMHz):ꢀδꢀ7.12ꢀ(m,ꢀ5H),ꢀ11.02ꢀ(s,ꢀ1H)ꢀandꢀ11.72ꢀ
1
13
(s,ꢀ1H);ꢀ CꢀNMRꢀ(DMSO,ꢀ22.5ꢀMHz):ꢀδꢀ110.77,ꢀ120.15,ꢀ122.16,ꢀ
DMSO‐d ꢀ asꢀ solvent.ꢀ Ultrasonicationꢀ wasꢀ performedꢀ inꢀ aꢀ
6
TRANSSONIꢀ660/Hꢀultrasoundꢀcleanerꢀwithꢀaꢀfrequencyꢀofꢀ35ꢀ
KHzꢀandꢀanꢀoutputꢀpowerꢀofꢀ70ꢀW.ꢀ ꢀ
2
.2.ꢀ ꢀ Preparationꢀofꢀtheꢀnano‐sizedꢀSiO
2
:FeCl ꢀcatalystꢀ
3
(
FeCl @SiO )ꢀ ꢀ
3
2
Inꢀaꢀtypicalꢀprocedure,ꢀnano‐sizedꢀSiO2ꢀ(0.25ꢀg)ꢀwasꢀaddedꢀtoꢀ
aꢀsolutionꢀ(1250ꢀppm)ꢀofꢀFeCl3ꢀ(31.25ꢀmg)ꢀinꢀdriedꢀEtOAcꢀ(25ꢀ
O
O
R
O
R
O
S
NH
N
FeCl @SiO2
3
+
HCl H2N
HCl H2N
N
R
N
H
NH2
EtOH‐H O (9:1)/
2
Reflux
R
S
O
R
O
R
NH
N
FeCl @SiO2
3
+
N
R
N
H
NH2
EtOH‐H O (9:1)/
2
Reflux
R
Schemeꢀ1.ꢀSynthesisꢀofꢀ1,2,4‐triazineꢀderivativesꢀwithꢀNSSSFe.ꢀ
Fig.ꢀ1.ꢀTheꢀTEMꢀimageꢀofꢀFeCl
3
@SiO .ꢀ
2

622ꢀ
DavoodꢀHabibiꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ36ꢀ(2015)ꢀ620–625ꢀ
1
C
5
30.32,ꢀ 130.92,ꢀ 1414.42,ꢀ 154.95ꢀ andꢀ 162.66;ꢀ Anal.ꢀ Calcdꢀ forꢀ
1
00
9 6 4
H N Oꢀ(%):ꢀCꢀ58.06,ꢀHꢀ3.25,ꢀNꢀ30.09,ꢀOꢀ8.59;ꢀFoundꢀ(%):ꢀCꢀ
20 nm FeCl @SiO2
3
9.04,ꢀHꢀ2.82,ꢀNꢀ30.38,ꢀOꢀ7.76.ꢀ
8
0
0
Snaphto[1,2‐e](1,2,4)‐triazin‐9‐olꢀ(Entryꢀ4).ꢀPaleꢀwhiteꢀsol‐
–1
1
id;ꢀmpꢀ =ꢀ281–283ꢀ ᵒC;ꢀIRꢀ(KBr,ꢀ cm ):ꢀνꢀ3470,ꢀ 3300,ꢀ1700;ꢀ Hꢀ
NMRꢀ(DMSO,ꢀ90ꢀMHz):ꢀδꢀ6.8–8.3ꢀ(m,ꢀ6H),ꢀ10ꢀ(s,ꢀ1H)ꢀandꢀ11.73ꢀ
6
30-70 nm FeCl @SiO2
3
(
1
s,ꢀ 1H);ꢀ 13Cꢀ NMRꢀ (DMSO,ꢀ22.5ꢀ MHz):ꢀ δꢀ 123.17,ꢀ 126.9,ꢀ 127.99,ꢀ
28.16,ꢀ128.52,ꢀ130.4,ꢀ133.54,ꢀ135.43,ꢀ136.87,ꢀ142.79,ꢀ155.40ꢀ
andꢀ156.15;ꢀAnal.ꢀCalcdꢀforꢀC13 Oꢀ(%):ꢀCꢀ70.58,ꢀHꢀ3.19,ꢀNꢀ
9.00,ꢀOꢀ7.23;ꢀFoundꢀ(%):ꢀCꢀ69.73,ꢀHꢀ3.82,ꢀNꢀ18.89,ꢀOꢀ7.74.ꢀ
Phenanthro[9,10‐e][1,2,4]triazin‐3‐olꢀ (Entryꢀ 5).ꢀ Paleꢀ lightꢀ
40
6
0-200 nm FeCl @SiO2
H N
7 3
3
1
20
20 nm SiO2
No catalyst
–1
yellowꢀsolid;ꢀmpꢀ=ꢀ229–231ꢀᵒC;ꢀIRꢀ(KBr,ꢀcm ):ꢀνꢀ3464,ꢀ3200,ꢀ
0
1
1
1
6
688;ꢀ HꢀNMRꢀ(DMSO,ꢀ90ꢀMHz):ꢀδꢀ7.7–8.7ꢀ(m,ꢀ9H)ꢀandꢀ14ꢀ(s,ꢀ
0
1
2
3
4
5
6
H);ꢀAnal.ꢀCalcdꢀforꢀC15
.47;ꢀFoundꢀ(%):ꢀCꢀ72.54,ꢀHꢀ3.19,ꢀNꢀ17.12,ꢀOꢀ7.15.ꢀ
1,2,4)‐Triazin‐3‐olꢀ (Entryꢀ 6).ꢀ Paleꢀ whiteꢀ solid;ꢀ mpꢀ =ꢀ
9 3
H N Oꢀ(%):ꢀCꢀ72.87,ꢀHꢀ3.67,ꢀNꢀ16.99,ꢀOꢀ
Time (h)
O
N
O
O
(
NH
N
FeCl @SiO2
3
Ph
NH
2
HCl
–1
1
2
16–218ꢀ ᵒC;ꢀ IRꢀ (KBr,ꢀ cm ):ꢀ νꢀ 3464,ꢀ 3200,ꢀ 1688;ꢀ Hꢀ NMRꢀ
+
H2N
N
H
Ph
EtOH‐H O (9:1)/
13
2
(
DMSO,ꢀ90ꢀMHz):ꢀδꢀ6.0ꢀ(s,ꢀ2H),ꢀ7.4ꢀ(s,ꢀ1H)ꢀandꢀ10.33ꢀ(s,ꢀ1H);ꢀ Cꢀ
NMRꢀ (DMSO,ꢀ 22.5ꢀ MHz):ꢀ δꢀ 145.17,ꢀ 150.9ꢀ andꢀ 161.99;ꢀ Anal.ꢀ
CalcdꢀforꢀC Oꢀ(%):ꢀCꢀ37.12,ꢀHꢀ3.11,ꢀNꢀ43.29,ꢀOꢀ16.48;ꢀFoundꢀ
%):ꢀCꢀ37.45,ꢀHꢀ3.82,ꢀNꢀ42.71,ꢀOꢀ16.02.ꢀ
,6‐Diethyl(1,2,4)‐triazin‐3‐olꢀ (Entryꢀ 7).ꢀ Paleꢀ lightꢀ yellowꢀ
O
Reflux
Ph
Ph
Fig.ꢀ2. Effectꢀofꢀcatalystꢀparticleꢀsizeꢀonꢀtheꢀrateꢀandꢀyieldꢀofꢀtheꢀmodelꢀ
reaction.ꢀ Reactionꢀ conditions:ꢀ benzilꢀ (1ꢀ mmol),ꢀ semicarbazideꢀ HClꢀ (1ꢀ
3 3 3
H N
(
mmol),ꢀsolidꢀcatalystꢀ(25ꢀmg),ꢀEtOH‐H Oꢀ(9:1,ꢀ5ꢀmL),ꢀreflux.ꢀ
2
5
–1
1
solid;ꢀmpꢀ=ꢀ219–220ꢀᵒC;ꢀIRꢀ(KBr,ꢀcm ):ꢀνꢀ3472,ꢀ3276,ꢀ1685;ꢀ Hꢀ
NMRꢀ(DMSO,ꢀ90ꢀMHz):ꢀδꢀ2.24–2.6ꢀ(m,ꢀ6H),ꢀ7.4ꢀ(m,ꢀ4H),ꢀ9.00ꢀ(s,ꢀ
sizesꢀofꢀSiO .ꢀTheꢀresultsꢀareꢀpresentedꢀinꢀFig.ꢀ2.ꢀ ꢀ ꢀ
2
Asꢀ shownꢀ inꢀ Fig.ꢀ 2,ꢀ inꢀ comparisonꢀ withꢀ theꢀ catalyst‐freeꢀ
condition,ꢀ theꢀ reactionꢀ rateꢀ andꢀ yieldꢀ wereꢀ bothꢀ improvedꢀ
whenꢀtheꢀreactionꢀwasꢀcarriedꢀoutꢀinꢀtheꢀpresenceꢀofꢀtheꢀcata‐
1
1
C
5
H)ꢀ andꢀ 10.22ꢀ (s,ꢀ 1H);ꢀ 13Cꢀ NMRꢀ (DMSO,
0.7,ꢀ 23.65,ꢀ 129.65,ꢀ 145.52ꢀ andꢀ 148.92;ꢀ Anal.ꢀ Calcdꢀ forꢀ
Oꢀ(%):ꢀCꢀ54.89,ꢀHꢀ7.24,ꢀNꢀ27.43,ꢀOꢀ10.44;ꢀFoundꢀ(%):ꢀCꢀ
4.00,ꢀHꢀ8.53,ꢀNꢀ26.45,ꢀOꢀ11.02.ꢀ ꢀ
H‐[1,2,4]triazino[5,6‐b]indole‐3(5H)‐thioneꢀ(Entryꢀ8).ꢀPaleꢀ
ꢀ
22.5ꢀ MHz):ꢀ δꢀ 10.39,ꢀ
7
H
11 3
N
lyst.ꢀInꢀaddition,ꢀbyꢀsupportingꢀFeCl
particleꢀ sizeꢀ ofꢀ SiO ,ꢀ theꢀ reactionsꢀ wereꢀ completedꢀ inꢀ shorterꢀ
times.ꢀTheseꢀresultsꢀcanꢀbeꢀexplainedꢀonꢀtheꢀbasisꢀofꢀtheꢀdiffer‐
encesꢀinꢀtheꢀFeCl ꢀcontentꢀonꢀSiO ꢀwithꢀvariousꢀparticlesꢀsizes.ꢀ
Toꢀproveꢀthis,ꢀtheꢀamountꢀofꢀadsorbedꢀFeCl3ꢀperꢀunitꢀmassꢀofꢀ
theꢀ adsorbentꢀ SiO ꢀ (mg/g),ꢀ q ,ꢀ wasꢀ calculatedꢀ usingꢀ Eq.ꢀ (1)ꢀ
whereꢀC ꢀandꢀC ꢀareꢀtheꢀinitialꢀandꢀfinalꢀconcentrationsꢀ(mg/Lꢀ=ꢀ
ppm)ꢀofꢀFeCl3ꢀrespectively,ꢀVꢀisꢀtheꢀsolutionꢀvolumeꢀ(L)ꢀandꢀmꢀisꢀ
theꢀmassꢀofꢀSiO ꢀasꢀadsorbentꢀ(g).ꢀ ꢀ ꢀ
ꢀ=ꢀ(C –C )V/mꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ (1)ꢀ
Byꢀusingꢀtheꢀatomicꢀabsorptionꢀtechniqueꢀforꢀdeterminingꢀ
,ꢀtheꢀamountꢀofꢀFeCl ꢀadsorptionꢀonꢀtheꢀvariousꢀparticleꢀsizesꢀ
ofꢀSiO2ꢀwasꢀdetermined.ꢀTheꢀFeCl ꢀcontentꢀperꢀgꢀofꢀsolidꢀcatalystꢀ
decreasedꢀasꢀtheꢀparticleꢀsizeꢀwasꢀincreasedꢀ(Fig.ꢀ3).ꢀ
3 2
ꢀonꢀSiO ꢀandꢀdecreasingꢀtheꢀ
2
2
–1
1
lightꢀyellowꢀsolid;ꢀmpꢀ=ꢀ254–257ꢀᵒC;ꢀIRꢀ(KBr,ꢀcm ):ꢀνꢀ3395;ꢀ Hꢀ
NMRꢀ (DMSO, 90ꢀ MHz):ꢀ δꢀ8ꢀ(m,ꢀ4H),ꢀ 11.5ꢀ(s,ꢀ1H)ꢀ andꢀ12.7ꢀ (s,ꢀ
H);ꢀ 13Cꢀ NMRꢀ (DMSO,ꢀ 22.5ꢀ MHz):ꢀ δꢀ 107.89,ꢀ 116.8,ꢀ 117.82,ꢀ
19.24,ꢀ 126.12,ꢀ 139.28,ꢀ 159.58ꢀ andꢀ 175.74;ꢀ Anal.ꢀ Calcdꢀ forꢀ
Sꢀ(%):ꢀCꢀ53.45,ꢀHꢀ2.99,ꢀNꢀ27.70,ꢀSꢀ15.86;ꢀFoundꢀ(%):ꢀCꢀ
3
2
ꢀ
1
1
C
5
2
e
0
e
9
H N
6 4
3.10,ꢀHꢀ3.2,ꢀNꢀ27.53,ꢀSꢀ16.17.ꢀ
2
Phenanthro[9,10‐e][1,2,4]triazine‐3(2H)‐thioneꢀ (Entryꢀ 9).ꢀ
q
e
0
e
–1
Paleꢀ lightꢀ yellowꢀ solid;ꢀ mpꢀ =ꢀ 218–222ꢀ ᵒC;ꢀ IRꢀ (KBr,ꢀ cm ):ꢀ νꢀ
1
3
1
1
391;ꢀ HꢀNMRꢀ(DMSO,ꢀ90ꢀMHz):ꢀδꢀ7.5–8.3ꢀ(m,ꢀ8H)ꢀandꢀ13.8ꢀ(s,ꢀ
C
e
3
H);ꢀ 13Cꢀ NMRꢀ (DMSO,
22.25,ꢀ131.14,ꢀ131.97,ꢀ142,ꢀ26,ꢀ162.55ꢀandꢀ178.71;ꢀAnal.ꢀCalcdꢀ
Sꢀ(%):ꢀCꢀ68.42,ꢀHꢀ3.45,ꢀNꢀ15.96,ꢀSꢀ12.18;ꢀFoundꢀ(%):ꢀ
Cꢀ68.12,ꢀHꢀ3.68,ꢀNꢀ16.23,ꢀSꢀ11.97.ꢀ
,6‐Diphenyl‐1,2,4‐triazine‐3(2H)‐thioneꢀ (Entryꢀ 10).ꢀ Paleꢀ
22.5ꢀ MHz):ꢀ δꢀ 110.93,ꢀ 119.87,ꢀ 120.84,ꢀ
ꢀ
3
forꢀC15
H N
9 3
3
.2.ꢀ ꢀ EffectꢀofꢀsolventꢀonꢀFeCl
3
ꢀadsorptionꢀonꢀnano‐sizedꢀSiO ꢀ
2
5
–1
1
whiteꢀsolid;ꢀmpꢀ=ꢀ212–214ꢀᵒC;ꢀIRꢀ(KBr,ꢀcm ):ꢀνꢀ3421;ꢀ HꢀNMRꢀ
(
(
1
1
DMSO,ꢀ 90ꢀ MHz):ꢀ δꢀ 7.3ꢀ (m,ꢀ 10H)ꢀ andꢀ 15.2ꢀ (s,ꢀ 1H);ꢀ 13Cꢀ NMRꢀ
DMSO, 22.5ꢀMHz):ꢀδꢀ126.0,ꢀ128.75,ꢀ155.97,ꢀ157.63,ꢀ169.13ꢀandꢀ
80.71;ꢀAnal.ꢀCalcdꢀforꢀC15 Sꢀ(%):ꢀCꢀ67.9,ꢀHꢀ4.18,ꢀNꢀ15.84,ꢀSꢀ
2.08;ꢀFoundꢀ(%):ꢀCꢀ68.25,ꢀHꢀ4.87,ꢀNꢀ15.31,ꢀSꢀ11.57.ꢀ
7
0
0
ꢀ
6
H N
11 3
50
40
30
20
10
0
3
.ꢀ ꢀ Resultsꢀandꢀdiscussionꢀ
3.1.ꢀ ꢀ Effectꢀofꢀtheꢀcatalystꢀparticleꢀsizeꢀ
Toꢀinvestigateꢀtheꢀeffectꢀofꢀtheꢀcatalystꢀparticleꢀsizeꢀonꢀtheꢀ
2
0
35-70
Particle size (nm)
ꢀcontentꢀinꢀFeCl @SiO ꢀofꢀdifferentꢀparticleꢀsizes.ꢀ
63-200
rateꢀandꢀyield,ꢀtheꢀreactionꢀbetweenꢀbenzilꢀ(1ꢀmmol)ꢀandꢀsemi‐
carbazideꢀHClꢀ(1ꢀmmol)ꢀinꢀaꢀEtOH‐H Oꢀ(9:1)ꢀmixtureꢀasꢀsolventꢀ
wasꢀstudiedꢀasꢀtheꢀmodelꢀreactionꢀunderꢀrefluxꢀusingꢀvariousꢀ
2
Fig.ꢀ3.ꢀFeCl
3
3
2

ꢀ
DavoodꢀHabibiꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ36ꢀ(2015)ꢀ620–625ꢀ
623ꢀ
60
50
40
30
20
10
0
60
40
20
0
EtOAc
EtOH
H
2
O
n-Hexane Acetone
0
500
1000
1500
2000
Solvent
ꢀadsorptionꢀonꢀtheꢀnano‐sizedꢀSiO
C
0
(ppm)
Fig.ꢀ4.ꢀFeCl
3
2
ꢀcatalystꢀwithꢀdifferent
Fig.ꢀ5.ꢀFeCl
FeCl .ꢀ
3
3
ꢀcontentꢀonꢀtheꢀFeCl @SiO ꢀcatalystꢀversusꢀconcentrationꢀofꢀ
2
solvents.ꢀ
3
Toꢀ optimizeꢀ theꢀ reactionꢀ conditions,ꢀ theꢀ effectsꢀ ofꢀ theꢀ
FeCl @SiO2ꢀ catalystꢀ andꢀ otherꢀ reactionꢀ parametersꢀ onꢀ theꢀ
modelꢀreactionꢀwereꢀstudiedꢀ(Tableꢀ2).ꢀ
TheꢀresultsꢀshownꢀinꢀTableꢀ2ꢀindicatedꢀthatꢀtheꢀbestꢀresultꢀinꢀ
termsꢀ ofꢀ theꢀ reactionꢀ rateꢀ andꢀ yieldꢀ wasꢀ obtainedꢀ whenꢀ theꢀ
Toꢀstudyꢀtheꢀeffectꢀofꢀtheꢀsolventꢀonꢀtheꢀadsorptionꢀprocess,ꢀ
nano‐sizedꢀ SiO ꢀ (0.25ꢀ g)ꢀ wasꢀ addedꢀ toꢀ theꢀ solutionsꢀ (1250ꢀ
ppm)ꢀ ofꢀ FeCl ꢀ (31.25ꢀ mg)ꢀ inꢀ variousꢀ solventsꢀ (25ꢀ mL)ꢀ andꢀ
stirredꢀforꢀ24ꢀh.ꢀTheꢀresultingꢀmixtureꢀwasꢀthenꢀworked‐upꢀandꢀ
theꢀcatalystꢀseparatedꢀbyꢀtheꢀprocedureꢀdescribedꢀabove.ꢀTheꢀ
3
2
3
2
reactionꢀwasꢀconductedꢀunderꢀrefluxꢀinꢀaꢀEtOH‐H Oꢀ(9:1)ꢀmix‐
FeCl
absorptionꢀfromꢀC
theꢀnano‐sizedꢀSiO
providedꢀtheꢀhighestꢀFeCl
3
ꢀ contentꢀ ofꢀ theꢀ catalystꢀ wasꢀ determinedꢀ byꢀ Fe3+ꢀ atomicꢀ
ꢀinꢀEq.ꢀ(1).ꢀTheꢀamountꢀofꢀFeCl ꢀadsorbedꢀonꢀ
ꢀwithꢀdifferentꢀsolventsꢀindicatedꢀthatꢀEtoAcꢀ
ꢀcontentꢀ(Fig.ꢀ4).ꢀ
tureꢀasꢀsolventꢀwithꢀFeCl @SiO ꢀwithꢀaꢀFeCl ꢀcontentꢀofꢀ66ꢀmgꢀ
3
2
3
e
3
perꢀgꢀcatalystꢀ(Entryꢀ5).ꢀAꢀdecreaseꢀinꢀtheꢀyieldꢀwasꢀobservedꢀ
whenꢀtheꢀreactionꢀwasꢀperformedꢀunderꢀultrasoundꢀirradiationꢀ
usingꢀaꢀsimilarꢀcatalystꢀcompositionꢀ(Entriesꢀ13ꢀandꢀ14).ꢀWhenꢀ
theꢀ reactionꢀ wasꢀ carriedꢀ outꢀ inꢀ theꢀ presenceꢀ ofꢀ unloadedꢀ
2
3
3
.3.ꢀ ꢀ EffectꢀofꢀFeCl
3
ꢀconcentrationꢀonꢀtheꢀFeCl ꢀcontentꢀofꢀtheꢀ ꢀ
3
2
nano‐SiO ,ꢀ theꢀ rateꢀ andꢀ yieldꢀ wereꢀ bothꢀ reducedꢀ significantlyꢀ
FeCl @SiO2ꢀcatalystꢀ ꢀ
3
(Entryꢀ 2).ꢀ Moreover,ꢀ inꢀ theꢀ absenceꢀ ofꢀ theꢀ catalyst,ꢀ theꢀ yieldꢀ
wasꢀveryꢀlowꢀ(Entryꢀ1).ꢀ
InꢀorderꢀtoꢀobtainꢀaꢀhighꢀefficiencyꢀofꢀtheꢀFeCl
tionꢀinꢀprovidingꢀtheꢀmostꢀadsorptionꢀonꢀnano‐sizedꢀSiO
examinedꢀ theꢀ FeCl3ꢀ contentsꢀ onꢀ theꢀ preparedꢀ catalystsꢀ usingꢀ
variousꢀconcentrationsꢀofꢀtheꢀFeCl ꢀsolution.ꢀDifferentꢀconcen‐
trationsꢀofꢀFeCl ꢀinꢀEtOAcꢀ(25ꢀmL)ꢀwereꢀplacedꢀinꢀsixꢀseparateꢀ
flasksꢀcontainingꢀnano‐sizedꢀSiO ꢀ(0.25ꢀg)ꢀandꢀstirredꢀatꢀroomꢀ
temperatureꢀforꢀ24ꢀh.ꢀTheꢀcontentꢀofꢀeachꢀflaskꢀwasꢀcentrifugedꢀ
andꢀfilteredꢀtoꢀseparateꢀtheꢀsolidꢀcatalystꢀwhichꢀwasꢀdriedꢀinꢀanꢀ
ovenꢀ atꢀ 100ꢀ ᵒC.ꢀ Finally,ꢀ theꢀ concentrationꢀ ofꢀ Fe3+ꢀ wasꢀ deter‐
3
ꢀconcentra‐
Inꢀ orderꢀ toꢀ establishꢀ theꢀ scopeꢀ ofꢀ thisꢀ methodology,ꢀ weꢀ
conductedꢀtheꢀreactionꢀofꢀsemicarbazideꢀorꢀthiosemicarbazideꢀ
withꢀaꢀseriesꢀofꢀα,β‐dicarbonylꢀcompoundsꢀwithꢀdifferentꢀsub‐
stituentsꢀunderꢀtheꢀoptimumꢀconditionsꢀ(Tableꢀ2,ꢀEntryꢀ5).ꢀAllꢀ
theꢀreactionsꢀproceededꢀsmoothlyꢀtoꢀaffordꢀtheꢀcorrespondingꢀ
productsꢀinꢀquantitativeꢀyieldsꢀasꢀsummarizedꢀinꢀTableꢀ3.ꢀ ꢀ
2
,ꢀweꢀ
3
3
2
Tableꢀ2ꢀ
Reactionꢀ parametersꢀ andꢀ catalyticꢀ activityꢀ ofꢀ theꢀ FeCl
withꢀtheꢀmodelꢀreaction.ꢀ
3
@SiO2ꢀ catalystꢀ
minedꢀbyꢀatomicꢀabsorptionꢀusingꢀC ꢀinꢀEq.ꢀ(1).ꢀTheꢀresultsꢀareꢀ
e
summarizedꢀinꢀTableꢀ1.ꢀ ꢀ
(
FeCl
3
ꢀcontent/ꢀ
,ꢀmg/g)
Time Isolatedꢀ
(h) yieldꢀ(%)
ItꢀisꢀevidentꢀthatꢀnoꢀsignificantꢀchangeꢀofꢀtheꢀFeCl
theꢀFeCl @SiO ꢀcatalystꢀoccurredꢀwithꢀincreaseꢀofꢀtheꢀconcen‐
trationꢀofꢀFeCl ꢀbeyondꢀ1250ꢀppmꢀ(Tableꢀ1,ꢀFig.ꢀ5).ꢀ ꢀ
3
ꢀcontentꢀofꢀ
Entry
Conditionꢀ
Refluxꢀ
Solventꢀ
EtOHꢀ
nano‐SiO
2
3
2
1ꢀ
Noꢀcatalystꢀ
6ꢀ
Traceꢀ
3
2ꢀ
Neatꢀnano‐SiO
2
Refluxꢀ
Refluxꢀ
Refluxꢀ
Refluxꢀ
Refluxꢀ
Refluxꢀ
Refluxꢀ
Refluxꢀ
Refluxꢀ
Refluxꢀ
40ꢀCꢀ
EtOHꢀ
EtOHꢀ
EtOHꢀ
6ꢀ
6ꢀ
6ꢀ
15ꢀ
58ꢀ
68ꢀ
3
ꢀ
22ꢀ
66ꢀ
66ꢀ
66ꢀ
66ꢀ
66ꢀ
66ꢀ
66ꢀ
66ꢀ
66ꢀ
66ꢀ
3.4.ꢀ ꢀ Optimizingꢀtheꢀreactionꢀconditionsꢀ
4
ꢀ
5
ꢀ
EtOH‐H
2
Oꢀ(9:1)ꢀ 6ꢀ
90ꢀ
6
ꢀ
DMSOꢀ
DMFꢀ
6ꢀ
6ꢀ
70ꢀ
60ꢀ
Tableꢀ1ꢀ
7
ꢀ
Effectꢀ ofꢀ FeCl
catalyst.ꢀ
3
ꢀ concentrationꢀ onꢀ theꢀ FeCl
3
ꢀ contentꢀ ofꢀ theꢀ FeCl @SiO2ꢀ
3
8
ꢀ
EtOH‐H
2
Oꢀ(1:1)ꢀ 6ꢀ
59ꢀ
9
ꢀ
CHCl3ꢀ
EtOAcꢀ
6ꢀ
6ꢀ
6ꢀ
Traceꢀ
Traceꢀ
36ꢀ
Entryꢀ
C
0
ꢀ(ppm)ꢀ ꢀ(ppm)
C
e
q
eꢀ
10ꢀ
11ꢀ
12ꢀ
13ꢀ
1
ꢀ
ꢀ 250ꢀ
ꢀ 500ꢀ
ꢀ 750ꢀ
1000ꢀ
1250ꢀ
1500ꢀ
1750ꢀ
2000ꢀ
ꢀ ꢀ 26.376ꢀ
ꢀ ꢀ 30.338ꢀ
ꢀ 223.272ꢀ
ꢀ 351.694ꢀ
ꢀ 580.782ꢀ
ꢀ 819.469ꢀ
1054.761ꢀ
1299.763ꢀ
22.3624ꢀ
46.9662ꢀ
56.6728ꢀ
64.8306ꢀ
66.9218ꢀ
68.0531ꢀ
69.5239ꢀ
70.0237ꢀ
H Oꢀ
2
2
ꢀ
EtOH‐H
2
Oꢀ(9:1)ꢀ 6ꢀ
Oꢀ(9:1)ꢀ 6ꢀ
23ꢀ
31ꢀ
3
ꢀ
Sonicationꢀ EtOH‐H
(50ꢀC)ꢀ
2
4
ꢀ
5
ꢀ
14ꢀ
66ꢀ
Sonicationꢀ EtOH‐H
(60ꢀC)ꢀ
2
Oꢀ(9:1)ꢀ 6ꢀ
38ꢀ
6
ꢀ
7
ꢀ
Reactionꢀ conditions:ꢀ benzilꢀ (1ꢀ mmol),ꢀ semicarbazideꢀ HClꢀ (1ꢀ mmol),ꢀ
solidꢀcatalystꢀ(25ꢀmg),ꢀsolventꢀ(5ꢀmL).ꢀ
8ꢀ

624ꢀ
DavoodꢀHabibiꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ36ꢀ(2015)ꢀ620–625ꢀ
Tableꢀ3ꢀ
Synthesisꢀofꢀ1,2,4‐triazineꢀderivativesꢀcatalyzedꢀbyꢀFeCl
3 2
@SiO .ꢀ
Entry
(Thio)ꢀsemicarbazide
Dicarbonyl
ꢀ Product
ꢀ m.p.ꢀ(ᵒC)
ꢀ 250–252
Yieldꢀ(%)
Timeꢀ(h)
5
a
ꢀ
ꢀ
97,ꢀ96ꢀ ,
1
ꢀ
b
ꢀc
94 ,ꢀ92
2
3
ꢀ 231–233
ꢀ 281–283
ꢀ 80
ꢀ 4
ꢀ 86
ꢀ 4
4
5
ꢀ 281–283
229–231
ꢀ 73
5
6
ꢀ 78
ꢀ
6
7
216–218
ꢀ 60
80
6
ꢀ 219–220
ꢀ 6
8
9
ꢀ 254–257
ꢀ 218–222
ꢀ 72
ꢀ 86
4
6
ꢀ
ꢀ
1
0
ꢀ 212–214
ꢀ 92
5
ꢀ
ꢀ
3.5.ꢀ ꢀ Recyclingꢀofꢀtheꢀcatalystꢀ
procedureꢀ gaveꢀ theꢀ productsꢀ inꢀ shorterꢀ reactionꢀ timesꢀ andꢀ
quantitativeꢀyields.ꢀ ꢀ
Inꢀorderꢀtoꢀstudyꢀtheꢀstabilityꢀandꢀreusabilityꢀofꢀtheꢀcatalyst,ꢀ
theꢀ reactionꢀ mixtureꢀ wasꢀ centrifugedꢀ afterꢀ theꢀ completionꢀ ofꢀ
theꢀreaction.ꢀTheꢀseparatedꢀsolidꢀwasꢀwashedꢀwithꢀethylꢀace‐
tateꢀ(2ꢀ×ꢀ5ꢀmL)ꢀandꢀdriedꢀunderꢀvacuumꢀ(20ꢀᵒC).ꢀTheꢀrecoveredꢀ
catalystꢀ wasꢀ reusedꢀ forꢀ threeꢀ consecutiveꢀ runsꢀ withoutꢀ anyꢀ
significantꢀlossꢀofꢀactivityꢀ(Tableꢀ3,ꢀEntryꢀ1).ꢀ
Acknowledgmentsꢀ
TheꢀauthorsꢀwishꢀtoꢀthankꢀfromꢀtheꢀBu‐AliꢀSinaꢀUniversity,ꢀ
Hamedanꢀ 6517838683ꢀ Iranꢀ forꢀ theꢀ financialꢀ supportꢀ ofꢀ thisꢀ
work.ꢀ
4.ꢀ ꢀ Conclusions
Referencesꢀ
FeCl
,2,4‐triazineꢀderivativesꢀinꢀEtOH/H
derꢀ reflux.ꢀ Inꢀ comparisonꢀ withꢀ otherꢀ reportedꢀ methods,ꢀ thisꢀ
3
@SiO
2
ꢀ isꢀ aꢀ suitableꢀ solidꢀ catalystꢀ forꢀ theꢀ synthesisꢀ ofꢀ
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